Teamsters’ president James Hoffa has written to Balfour Beatty chief executive Ian Tyler backing the Unite union in its opposition to plans to replace the JIB pay and conditions agreement with a new deal known as BESNA.

Hoffa said: “If this dispute is not resolved to the satisfaction of my colleagues in the UK we will have no option but to demonstrate our support.

“I am sure that neither of us would welcome this development.”

Balfour’s electrical division BBES is one of seven contractors due to quit the JIB and implement the new BESNA deal.

Unite members have voted for industrial action at BBES but the ballot is being challenged by the company.

Hoffa said in his letter to Tyler: “I am requesting in the strongest possible terms that you now personally intervene in this dispute and demand that the management of BBES change course.

“Your company must seek to negotiate with Unite on the basis of existing joint industrial bargaining arrangements, not the so-called BESNA proposals, which I know will remain unacceptable to workers in the UK.”

Despite the concerns of the Americans, the seven breakaway contractors confirmed this week that nearly 90% of workers have signed-up to the BESNA deal.

A Balfour Beatty spokesman said: “We can acknowledge receipt of this letter and  Mr Tyler will be responding to the head of the Teamsters in writing in due course.”